The present invention relates to magnetic hard disk drives. More specifically, the present invention relates to electrical connections for micro-actuators.
In the art today, different methods are utilized to improve recording density of hard disk drives. FIG. 1 provides an illustration of a typical disk drive with a typical drive arm 102 configured to read from and write to a magnetic hard disk 104. Typically, voice-coil motors (VCM) 106 are used for controlling a hard drive's arm 102 motion across a magnetic hard disk 106. Because of the inherent tolerance (dynamic play) that exists in the placement of a recording head 108 by a VCM 106 alone, micro-actuators 110 are now being utilized to ‘fine-tune’ head 108 placement. A VCM 106 is utilized for course adjustment and the micro-actuator 110 then corrects the placement on a much smaller scale to compensate for the VCM's 106 (with the arm 102) tolerance. This enables a smaller recordable track width, increasing the ‘tracks per inch’ (TPI) value of the hard drive (increased drive density).
FIG. 2 provides an illustration of a micro-actuator as used in the art. Typically, a slider 202 (containing a read/write magnetic head; not shown) is utilized for maintaining a prescribed flying height above the disk surface 104 (See FIG. 1). Micro-actuators may have flexible beams 204 connecting a support device 206 to a slider containment unit 208 enabling slider 202 motion independent of the drive arm 102 (See FIG. 1). An electromagnetic assembly or an electromagnetic/ferromagnetic assembly (not shown) may be utilized to provide minute adjustments in orientation/location of the slider/head 202 with respect to the arm 102 (See FIG. 1).
The electric trace connection connecting the micro-actuator to the printed circuit assembly currently passes over the suspension assembly, or suspension tongue. This design results in an increased stiffness in the suspension assembly due to the electric trace connection. Further, micro-actuator bonding, using methods such as gold ball bonding or solder bump bonding, is difficult as the bonding pad is located on the micro-actuator moving beam. Not enough support space exists to connect the micro-actuator. Also, the bonding process can damage the micro-actuator beam due to pressure or bonding force. The lower stiffness of the electric traces also makes it easier to deform the trace connection.